SteamOS

As far as I understand it, a second pc (or pc like device, they have some more announcements in the next few days, one of which might be a dedicated streaming box,perhaps something like a roku)

You still need a actual gaming pc with the capability to run the games at the settings you would want.

Well naturally you'd need the pc (I didn't drop 1500 just so steam could release their own console), So i guess it more or less acts like a media server? I smell latency issues but i'm pretty confident that valve will do a good job with it.